Trait Information: Bobtail, also known as Brachyury, is a naturally occurring short tail.

Inheritance Information: Bobtail is autosomal dominant, meaning that animals with just one copy of this allele will show the phenotype, and 50% of their offspring will also show this trait. This trait is homozygous lethal, meaning that individuals with two copies of the allele do not survive to birth.

The possible genotypes are:n/n The dog has a normal length tail.

B/n The dog has a short tail, and can pass the allele on to approximately 50% of any offspring. If bred to another B/n bobtail dog, approximately 25% of the offspring will have normal tails (n/n), 50% will be bobtail (B/n), and 25% will not be born. Therefore, when a litter is born, the expected ratio would be 33% normal tailed, 66% bobtail. If bred to a dog with a normal length tail (n/n), approximately 50% will be bobtail and 50% will be normal tailed.Recommendations:
– If breeding two bobtail dogs, expect to have slightly reduced litter sizes, because 25% of expected pups will not be born.

Test Information: This mutation test identifies a single base change in the T gene. Be aware that there are short tailed dogs for which the trait is not caused by this mutation.